1. Field of the Invention
The present invention relates to an FED, and particularly relates to an FED including an insulating supporting device with a reflection layer.
2. Background of the Invention
There are several categories of a flat panel display (FPD), such as, for example, a field emission display (FED), a thin film transistor-liquid crystal display (TFT-LCD), a plasma display panel (PDP), an organic electro-luminescence display (OELD), or a reflection-type liquid crystal display (LCD). Thinness, lightness, low power consumption, and portability are the common features of the FEDs mentioned above. The FED has many similarities with conventional cathode ray tubes (CRT). As for the CRT, electrons are accelerated in a vacuum towards phosphors, which then glows. The main difference with the CRT is that the electrons are generated by field emission rather than thermal emission, so the device consumes much less power and can be turned on instantly. Instead of one single electron gun, each pixel includes several thousands of sub-micrometer or even nanometer tips from which electrons are emitted. The tips, made of low work-function materials, and in particular of carbon nanotubes (CNTs) nowadays, are sharp, so that the local field strengths become high enough for even a moderately low gate voltage.
A conventional FED illustrated in FIG. 1 includes a unit within an anode 10a and a cathode 20a disposed therein, and an insulating supporting member 15a (or a spacer) arranged between the anode 10a and the cathode 20a for separating the anode 10a from the cathode 10a and supporting the anode 10a. The anode 10a includes an anode glass substrate 11a, an anode conductive layer 12a, and a phosphors layer 13a arranged sequentially. The cathode 20a includes a cathode glass substrate 21a, a cathode electrode layer 22a, a cathode electron emitter layer 23a, a dielectric layer 24a, and a gate layer 25a arranged sequentially. The insulating supporting member 15a is connected between the anode 10a and the cathode 10a for support. The cathode electron emitter layer 13a generates electrons for emission onto the phosphors layer 13a to produce light via an additional electric field, so as to excite the phosphors layer 13a to luminesce. Furthermore, the cathode electrode layer 22a is made from cathode conductive lines parallel to one another, and the gate layer 25a is made from gate conductive lines parallel to one another. The gate conductive lines are orthogonal to the cathode conductive lines. In addition, an additional voltage is forced between the gate layer 25a and the cathode electrode layer 22a. An electron beam provided by the gate layer is controlled to switch due to the orthogonal arrangement between the gate conductive lines and the cathode conductive lines. For ease of moving the electrons, a vacuum of 10−7 Torr is accordingly formed therein, a mean free path of the electrons is provided, and, furthermore, the vacuum protects the cathode electron emitter layer 223a and the phosphors layer 13a from pollution. In order to accelerate the electrons for impact, there should be a proper distance between the anode 10a and the cathode 20a. After the anode 10a, including the anode conductive layer 12a and the phosphors layer 13a, is provided with the high power, the electron beam is energized enough to excite the phosphors.
However, conventional methods make the conventional FED still hard to mass-produce due to the complicated procedures and the precise fabrications, especially for displays with large sizes. Other conventional methods using a thick film technology can be used for large size displays, but still do not provide high resolution. In addition, the relative pastes and materials are hard to implant.
In recent years, a new insulating supporting member is shaped of a panel as a rib. Referring to FIG. 1, an expansion coefficient of this material is similar to that of glass. The thickness of the plate-like device ranges from 500 μm to 1500 μm, and the plate-like device has a plurality of apertures 42′ etched therein. A diameter of each aperture 42′ can meet the FED unit (including the anode and the cathode). The plate-like device is used for a support. The conventional supporting member is shaped as a glass ball, a cross, or a strip via an adhesive stuck thereto in advance. After a sintering process, a plate-like device is made thereby. The supporting member has a size ranging from 50 μm to 200 μm. Because of the micro size, the plate-like device encounters some problems in manufacture. First, the manufacturing process is complicated. The equipment needs more precision due to the micro size. Second, the plate-like device sticky with the adhesive is polluted easily; because the conventional plate-like device uses the adhesive to connect to a panel and a sintering process is required, the adhesive easily pollutes the panel. Third after the sintering process, the solvent contained in the adhesive will escape therefrom to pollute the panel.
Hence, an improvement over the prior art is required to overcome the disadvantages thereof.